ABSTRACT Alcohol misuse by college students results in over 1,500 deaths per year21. Thus, it is crucial that we understand factors that promote excessive alcohol use by college students. Most commonly, college students report drinking for social facilitation purposes. While much research has evaluated those who drink for social rewards, less research has focused on whether individuals may have greater sensitivity to social rewards versus other rewards (e.g. monetary). Preliminary studies have found this broad social motivation (BSM) to be predictive of changes in drinking behavior over and above social drinking motives. Thus, further exploration into the circumstances in which those with BSM are more susceptible to heavy drinking is warranted. This study proposes to fill that gap by looking at how individual differences in BSM may interact with different peer groups to lead to heavier drinking. Further, this study will use innovative multimethod approaches to help us understand how changes in self-reported risk-taking assessed in a group setting as compared to an individual setting, as well as self-administered amount of drinking in a controlled lab setting, may translate to naturalistic behavior as measured through daily diary. College students over the age of 21 (N=100) will be randomized to complete an ad-lib drinking paradigm in either a group of their close friends, or a group of other college peers. Participants will then use daily diary to report their social context and drinking behaviors in natural settings. This multimethod approach will allow us to evaluate how behavior assessed in the lab predicts naturally occurring behaviors in an uncontrolled setting. For example, we will assess whether greater increases in self- reported risk-taking from baseline to after entering peer groups in the bar lab setting will predict heavier drinking on nights when most drinking companions are close friends reported during daily diary. Findings from this study could identify a high risk group of students who may be more sensitive to social rewards and social influences on drinking. This is innovative because research has demonstrated the importance of social motives in drinking behavior, yet, we have not determined the best way to predict who is most likely to engage in drinking for social facilitation. This study is aligned with the strategic plan of the National Institute on Alcohol Abuse and Alcoholism (NIAAA), as it has implications for improving strategies to prevent alcohol misuse and alcohol-related consequences in this high risk developmental period. This research also supports the goal of NIAAA-funded research having enhanced public impacts, as this study could help frame college and university policies on campus social outlets. The funding of this project will provide substantial training to an emerging predoctoral researcher in ethics, advanced and multimethod approaches to research, quantitative methods, and career development. Overall, this project will shed light on how reward sensitivity specific to social context may influence drinking behavior, with implications for prevention and public policy for college drinking.